Photoconductive (PC) drums have long been used in electrophotographic (EP) processes for transferring imaging data. They have a surface that gets charged to a uniform potential by a charge roller/corona/etc. and selectively discharged to create a latent electrostatic image for development with toner for transfer to media. They are installed as replaceable components of imaging devices, e.g., laser printers, copiers, fax machines, multifunction devices, etc. They come packaged as stand-alone units or as parts of toner cartridges. Manufacturers continually design them to decrease their wear rates and improve longevity. Certain embodiments add a lubricant. An applicator brush scrapes the lubricant and transfers it to a drum surface at a transfer nip during rotation of both the brush and the drum. An elongate rod contacts the brush to flicker away any residual particles stuck to the brush. A cleaning blade also scrapes clean the surface of the drum.
As has been noticed by the inventors, however, the lubricant builds up over time on the drum surface in locations that become less frequently developed with toner. Such has been found to cause variations of charge resistivity at the drum surface and noted to introduce particulate contamination in EP components or the toner. Problems in printed media have even been observed in the form of streaks or mottled defects.